<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            /* 怪异盒子模型的宽度和高度包含了内边距和边框 */
            box-sizing: border-box;
            width: 200px;
            height: 200px;
            background-color: rgb(52, 54, 173);
            padding: 50px;
            border: 10px dashed black;
            margin: 10px;
            box-sizing: border-box;
        }
    </style>
</head>

<body>
    <div class="box">我是一个段落</div>
</body>

</html>